JEE Main 2020ChemistryThermodynamics (C)MediumNumerical

JEE Main 2020 — Thermodynamics (C) Question with Solution

JEE Main 2020 (02 Sep Shift 1)

Question

The internal energy change (in J) when 90 g of water undergoes complete evaporation at 100°C is ..............

(Given : ΔHvap for water at 373 K=41 kJ/mol, R=8.314 JK-1 mol-1)

Enter your answer

Show full solutionCorrect answer: 189494
Correct answer
189494

Step-by-step explanation

Number of moles of water =9018=5 moles

ΔH=ΔU+ΔngRT

41000X5=ΔU+5×8.314×373

205000=ΔU+15505.61

ΔU=189494.39 J=189494 J

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About this question

This is a previous-year question from JEE Main 2020, covering the Thermodynamics (C) chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.